public class CBCBlockCipher extends java.lang.Object implements BlockCipher
Modifier and Type | Field and Description |
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private int |
blockSize |
private byte[] |
cbcNextV |
private byte[] |
cbcV |
private BlockCipher |
cipher |
private boolean |
encrypting |
private byte[] |
IV |
Constructor and Description |
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CBCBlockCipher(BlockCipher cipher)
Basic constructor.
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Modifier and Type | Method and Description |
---|---|
private int |
decryptBlock(byte[] in,
int inOff,
byte[] out,
int outOff)
Do the appropriate chaining step for CBC mode decryption.
|
private int |
encryptBlock(byte[] in,
int inOff,
byte[] out,
int outOff)
Do the appropriate chaining step for CBC mode encryption.
|
java.lang.String |
getAlgorithmName()
return the algorithm name and mode.
|
int |
getBlockSize()
return the block size of the underlying cipher.
|
BlockCipher |
getUnderlyingCipher()
return the underlying block cipher that we are wrapping.
|
void |
init(boolean encrypting,
CipherParameters params)
Initialise the cipher and, possibly, the initialisation vector (IV).
|
int |
processBlock(byte[] in,
int inOff,
byte[] out,
int outOff)
Process one block of input from the array in and write it to
the out array.
|
void |
reset()
reset the chaining vector back to the IV and reset the underlying
cipher.
|
private byte[] IV
private byte[] cbcV
private byte[] cbcNextV
private int blockSize
private BlockCipher cipher
private boolean encrypting
public CBCBlockCipher(BlockCipher cipher)
cipher
- the block cipher to be used as the basis of chaining.public BlockCipher getUnderlyingCipher()
public void init(boolean encrypting, CipherParameters params) throws java.lang.IllegalArgumentException
init
in interface BlockCipher
encrypting
- if true the cipher is initialised for
encryption, if false for decryption.params
- the key and other data required by the cipher.java.lang.IllegalArgumentException
- if the params argument is
inappropriate.public java.lang.String getAlgorithmName()
getAlgorithmName
in interface BlockCipher
public int getBlockSize()
getBlockSize
in interface BlockCipher
public int processBlock(byte[] in, int inOff, byte[] out, int outOff) throws DataLengthException, java.lang.IllegalStateException
processBlock
in interface BlockCipher
in
- the array containing the input data.inOff
- offset into the in array the data starts at.out
- the array the output data will be copied into.outOff
- the offset into the out array the output will start at.DataLengthException
- if there isn't enough data in in, or
space in out.java.lang.IllegalStateException
- if the cipher isn't initialised.public void reset()
reset
in interface BlockCipher
private int encryptBlock(byte[] in, int inOff, byte[] out, int outOff) throws DataLengthException, java.lang.IllegalStateException
in
- the array containing the data to be encrypted.inOff
- offset into the in array the data starts at.out
- the array the encrypted data will be copied into.outOff
- the offset into the out array the output will start at.DataLengthException
- if there isn't enough data in in, or
space in out.java.lang.IllegalStateException
- if the cipher isn't initialised.private int decryptBlock(byte[] in, int inOff, byte[] out, int outOff) throws DataLengthException, java.lang.IllegalStateException
in
- the array containing the data to be decrypted.inOff
- offset into the in array the data starts at.out
- the array the decrypted data will be copied into.outOff
- the offset into the out array the output will start at.DataLengthException
- if there isn't enough data in in, or
space in out.java.lang.IllegalStateException
- if the cipher isn't initialised.